Test sensors (e.g., biosensors) containing reagents are often used in assays for determining the analyte concentration in a fluid sample. The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, lactate, cholesterol, and bilirubin should be monitored in certain individuals. In particular, determining glucose in body fluids is important to diabetic individuals who must frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. Each test requires that a new test sensor be used, and thus, a number of test sensors may be used in a single day. Cartridges that contain a number of test sensors are used to allow users to carry multiple sensors around within a single object. The cartridge may utilize a drum or a disk to store the test sensors individually, or the cartridge may contain a plurality of stacked sensors. These cartridges may then be incorporated directly into a meter.
The reagents used to assist with the determination of the analyte concentration are typically sensitive to water and deteriorate if exposed for a period of time. Desiccants are utilized to minimize the exposure of the reactants to water and water vapor. To maintain the desiccant over time, the desiccant must be sealed off from the external atmosphere. In a drum or a disk cartridge, the test sensors are stored in individual compartments and both a sensor and a desiccant are sealed in the compartment. However, these types of cartridges typically result in low space efficiency and a higher cost for sealing each of the plurality of individual compartments.
In a cartridge containing stacked sensors, a separate desiccation chamber is provided that contains a desiccant for desiccating the entire cartridge. To maintain the desiccant, each of the openings to the cartridge is generally sealed. However, for a test sensor to be dispensed, at least one of the seals must be opened to allow a test sensor to exit the cartridge. In cartridges where foil is used to seal the openings, once the first test sensor has been dispensed, it is typical for the cartridge to remain exposed. In other stacked-sensor cartridges, the slot from which the test sensor is ejected is resealable, but at least a second opening is required through the cartridge to allow an ejection mechanism to eject the test sensor. This second opening may increase the potential for exposure of both the reagents and the desiccant to the external environment.
Thus, there exists a need for an improved test-sensor cartridge for efficiently storing and maintaining test sensors.